+
+/* When the boot image header has a version of 2, the structure of the boot
+ * image is as follows:
+ *
+ * +---------------------+
+ * | boot header | 1 page
+ * +---------------------+
+ * | kernel | n pages
+ * +---------------------+
+ * | ramdisk | m pages
+ * +---------------------+
+ * | second stage | o pages
+ * +---------------------+
+ * | recovery dtbo/acpio | p pages
+ * +---------------------+
+ * | dtb | q pages
+ * +---------------------+
+ *
+ * n = (kernel_size + page_size - 1) / page_size
+ * m = (ramdisk_size + page_size - 1) / page_size
+ * o = (second_size + page_size - 1) / page_size
+ * p = (recovery_dtbo_size + page_size - 1) / page_size
+ * q = (dtb_size + page_size - 1) / page_size
+ *
+ * 0. all entities are page_size aligned in flash
+ * 1. kernel, ramdisk and DTB are required (size != 0)
+ * 2. recovery_dtbo/recovery_acpio is required for recovery.img in non-A/B
+ * devices(recovery_dtbo_size != 0)
+ * 3. second is optional (second_size == 0 -> no second)
+ * 4. load each element (kernel, ramdisk, second, dtb) at
+ * the specified physical address (kernel_addr, etc)
+ * 5. If booting to recovery mode in a non-A/B device, extract recovery
+ * dtbo/acpio and apply the correct set of overlays on the base device tree
+ * depending on the hardware/product revision.
+ * 6. prepare tags at tag_addr. kernel_args[] is
+ * appended to the kernel commandline in the tags.
+ * 7. r0 = 0, r1 = MACHINE_TYPE, r2 = tags_addr
+ * 8. if second_size != 0: jump to second_addr
+ * else: jump to kernel_addr
+ */
+